Students come to school for an exam of mathematics at the Pre-University Jose Marti in Old Havana, Cuba, Monday. Eight people are under arrest in connection with a scandal involving the illicit sale of university entrance exams, Cuban authorities said Monday, days after thousands of high school students were forced to retake the test.

HAVANA — Eight people are under arrest in connection with a scandal involving the illicit sale of university entrance exams, Cuban authorities said Monday after thousands of high school students were forced to retake the test.

The unnamed suspects include five teachers, a methodologist, an employee at the Ministry of Higher Education’s printer’s office and a person not linked to the education sector. There was no word on possible criminal charges, but prosecutors were collecting evidence to present to the courts.

“It has been confirmed ... that the leaked materials were unscrupulously commercialized by the five teachers implicated, some of whom sold the exams while others reviewed the content with the students, charging for the service,” Monday’s announcement said.

The investigation into the scandal has been a fixture in state media for weeks, and the announcement called it a “matter of great sensitivity.”

In a signal of how seriously officials are taking the case, the message was signed by three Cabinet ministries including Interior — the arm of government that oversees policing and state security.

Education, which is universal and free including the university level, is considered sacrosanct as one of the “pillars” of Fidel Castro’s 1959 revolution.

However stories of teachers selling grades to augment their meager salaries are relatively common, if not widely publicized. There have also been past incidents of final exams leaking out prior to the test day.

But this is the first time authorities have made such a fuss about it — apparently in hopes of discouraging others by making an object lesson of the suspects.

“The final results of (the investigation) will be made public in a timely manner, since such acts, which attack the prestige of our educational system, will never go unpunished and will always be repudiated by our teachers, parents and students,” the ministries’ note said.

Current President Raul Castro’s government has waged a wider crackdown on corruption that has swept up dozens of Cuban officials and executives, as well as a number of foreign businesspeople.

Shortly after the nationwide exam was given early last month, rumors began circulating that the math, language and history sections had all been on sale beforehand for about $60 per subject.

Authorities publicly acknowledged the scandal May 20, nullifying the results for thousands of students in Havana and obliging them to take a replacement test six days later.

Twin 18-year-old sisters Lili and Rocio Garcia, who spent four months preparing for the test, said the make-up was noticeably more difficult.

“It was right to repeat the exam, but they should have done it in the whole country,” said Lili, who scored a perfect 100 initially and 95 the second time around. “It was not something that could go unpunished.”

Her sister disagreed, saying it wasn’t fair to punish everyone for the transgressions of others.

“It’s a lack of respect,” said Rocio, who saw her score fall from 99 to 91. “They didn’t have to repeat it.”